A recent development in the field of three dimensional printing technology is the application 3D printing to the printing of food. For printing food, the printed fluid will in many cases comprise a suspension fluid, i.e. a fluid comprising particles of an edible substance. However, not confined to the area of 3D printing of foods, the printing of suspension fluids is applicable in many other areas wherein arbitrary materials need to be printed (e.g. metals, organic materials, ceramics). For example, it is likewise applicable in the fields of pharmaceutics, printed electronics, or the printing of multi-material structures, and may generally be applied in spray drying applications for creating powders.
Efficient printing requires the use of highly filled suspension fluids, i.e. suspension fluids having a relative large particle density. However, a disadvantage of the printing of such highly filled suspensions is the clogging of printing nozzles. A too large particle size does not completely explain this problem. Even with highly filled suspensions of small particles (relative to the diameter of the nozzle outlet), clogging is experienced. In an industrial printing process, each clogging event requires intervention and maintenance, thereby interrupting the process and lowering the yield.
To overcome clogging, some solutions rely on filtration of larger particles using a filter. However, the use of filters is itself not desirable in industrial processes, because such filters require to be cleaned or replaced often during operation. Moreover, as noted, clogging is experienced even with suspensions of small particles.